I love Qubes also; very secure and quite flexible, but it requires a little more effort. Its also very picky about what hardware it will work with (especially if you want all the features operating). But it has a very limited market share (I think an estimated installed base of about 30,000). It basically uses the Xen hypervisor to create multiple virtual machines that are designed to be isolated -- if one is compromised, the others remain secure. It comes with Whomix and Fedora, but there are prebuilt templates for Debian and Arch, and you can even create a Windows 7 machine that works quite well!
I have a computer that multiboots into 7 OSs -- Mint, Manjaro, Windows, Fedora, openSUSE, Debian and Xubuntu. I was surprised, but everyone in the house -- my young granddaughter, college age step son, older step-daughter, etc. -- they all choose Manjaro. I think right now it is rated number 2 at DistroWatch, and its been around for a while.
Mint is very easy for new users (especially those coming from windows), but its security (compared to other distros) does leave something to be desired. I've always liked openSUSE, but it seems bloated and slow, even on a i7-3770K with 16G RAM. Debian is a battleship -- i.e., stable and secure. For me, half the fun is trying out new distros, so I have several computers set to multi-boot. Fedora is cutting edge, Xubuntu is fast, even on my old laptop with 1G RAM. And there are so many more out there.
But, to answer your question, it depends on what you want. Check out DistroWatch, most of the distros in the top 20 will be around for quite some time to come, although that's probably true for at least the top 50. Figure out what your next priority is (speed, minimal hardware requirements, security, stability, package diversity, ease of use, etc.). Then try out several -- either in Virtual Machines or using live disks (or USBs). You may find half the fun is experimenting, you will probably find all sort of little features you love and in the end you will get a distro (or multiboot into multiple distros) that you will be quite happy with -- especially since you found them.
Good luck, and enjoy.